35 Tapping

Taps and dies are cutting tools. A tap is used to cut the female portion of the mating pair (i.e., a nut). A die is used to cut the male portion of the mating pair (i.e., a bolt). The process of cutting threads using a tap is called tapping, whereas the process using a die is called threading. Both tools can be used to clean up a thread, which is called chasing. (ref: https://en.wikipedia.org/wiki/Tap_and_dieLinks to an external site.)

How to tap steel